Coastal Sand Dunes Research Articles

Alyssum montanum subsp. gmelinii, a rare plant species from coastal sand dunes, as a potential Ni accumulator: comparison with Alyssum murale

Alyssum montanum subsp. gmelinii, a rare plant species from coastal sand dunes, as a potential Ni accumulator: comparison with Alyssum murale

Arbuscular mycorrhizal fungus inocula from coastal sand dunes arrest olive cutting growth under salinity stress.

Cultivation of olive trees covers large coastal areas of land in Mediterranean regions, many of them characterized by low soil fertility and exposed to salinity and seasonal drought. In this frame, we developed mixed community inocula of arbuscular mycorrhizal fungi (AMF) derived from the extreme, seasonally arid environments of six Mediterranean sand dunes and evaluated their effects, in the form of community inocula, on rooted semi-woody olive tree cuttings (Olea europaea cv. Koroneiki). The plantlets were grown in the greenhouse for 10 months under 50 mM and 100 mM concentrations of NaCl, successively applied to induce osmotic stress. Inoculation had a positive effect on plant growth and nutrient uptake. However, the three best-performing inocula in early colonization and in plant growth enhancement also resulted in high plant sensitivity to high salinity, which was not observed for the other three inocula. This was expressed by decreased nutrient uptake and drastically lower plant growth, plant photosynthesis, and stomatal conductance (generally an over 50% reduction compared to no salinity application). Amplicon sequencing analysis of the olive plants under salinity stress showed that the AMF communities in the roots were clearly differentiated by inoculation treatment. We could not, however, consistently associate the plant responses observed under high salinity with specific shared AMF community membership or assembly attributes. The observed physiological overreaction to osmotic stress may be an adaptation trait, potentially brought about by host selection coupled to abiotic environmental filtering, in the harsh conditions from which the AMF inocula were derived. The overreaction may, however, be undesirable if conveyed to allochthonous plants at an agronomic level.

Habitat variations affect morphological, reproductive and some metabolic traits of Mediterranean Centaurea glomerata Vahl populations

Centaurea glomerata Vahl is an annual, monoecious and herbaceous member of Asteraceae, found in some localities of different topographic features/habitat conditions along the Mediterranean coastal region of Egypt. This study aimed to investigate some environmental gradients including edaphic and climate criteria on morphological, reproductive traits as well as phenolic and flavonoid metabolites in this species. Three distinct populations were selected. Two of them were located in coastal sand dunes (found in Rosetta region in Egypt); one was located on flat sand dunes, whereas the other grown on sloping ones. Meanwhile, the third population was represented in the rocky hillside of Burg El Arab region. The population detected in the sloping sand dunes showed best morphological and reproductive features, whilst the opposite was true for that represented on the rocky hillside. Moreover, the free phenolic and flavonoid compounds prevailed in the later. The meteorological data revealed that the rocky hillside received relatively lower minimum temperature and higher solar irradiance, while the sand dunes of Rosetta showed more warmer conditions. Light intensity and wind speed were reduced on the sloping sand dunes. The Canonical Correspondence Analysis (CCA) exhibited a clear correlation between most of metabolites detected and the population found on the rocky hillside along with higher solar irradiance prevails. The morpho-reproductive traits were related to climatic gradients and some soil criteria. These results revealed that the changes in micro-topography, that may lead to change in soil and climate variables, is the most important environmental gradient that controls the morphological and biochemical features of C. glomerata. Solar irradiance and/or light intensity are key factors playing a role influencing the measured traits of this species. These findings suggest that accumulation of secondary metabolites could be a biochemical strategy and an adaptational criterion for such species under stress conditions.

Endophytic Fungi of Salt Adapted <i>Ipomea pes-caprae</i> L. R. Br: their Possible Role in Inducing Salinity Tolerance in Paddy (<i>Oryza sativa</i> L.)

Endophytic fungi occur ubiquitously in all plants. Though their origin and evolution is enigmatic, they are known to play an important role in plant growth and development. Here we explore the endophytic fungal diversity of a perennial cree ping vine, Ipomea pes-caprae (family Convolulaceae), occurring naturally in the coastal sand dunes of peninsular India. Of the ten endophytes isolated from the plant, Fusarium oxysporum (MH511104) was found to grow even at 2 M NaCl in potato dextrose agar medium. The fungus was able to successfully colonize and impart salinity tolerance to salt -sensitive paddy variety, IR-64. We discuss these results in the context of increasing global interest on endophytes as a possible alternative route to crop i mprovement.

<p><strong><em>Salacia frutiplatensis </em>(Celastraceae, Salacioideae), a new species of the coastal sand dunes of Los Tuxtlas, Veracruz, Mexico</strong></p>

The new species Salacia frutiplatensis is described and illustrated herein. This new taxon is part of the arboreal strata of the coastal sand dunes scrub of Los Tuxtlas, Veracruz, Mexico, where it is considered endemic. Salacia frutiplatensis is similar to S. elliptica, S. cordata, and S. impressifolia, but differs from these in the shape and diameter of the extra-staminal disk, pericarp thickness, greater number of seeds, and not displaying the lianous habit.

Effect of Invasive Alien Species on the Co-Occurrence Patterns of Bryophytes and Vascular Plant Species—The Case of a Mediterranean Disturbed Sandy Coast

Cross-taxon analyses can explain patterns of interaction between taxa and their application in conservation studies can drive management actions. In a coastal sand dune system characterized by a high human pressure, we explored the co-occurrence patterns between vascular plants and bryophytes, with a focus on how the occurrence of invasive alien species (IAS) can affect those taxa and their relationships. Species congruences were evaluated at the community level considering taxonomic and functional diversities. Predictive co-correspondence analysis (Co-CA) was applied to quantify the strength of vascular plant communities in predicting bryophytes species composition. The relationship between the composition of vascular plants and bryophytes was significant, even if weak. Altitude and percentage of bare soil cover are the environmental variables exerting greater influence on the two taxa. The presence of IAS affects communities in an opposite way: for vascular plants, species richness increases with the presence of invasive alien species; for bryophytes, IAS’s presence has a low but significant negative influence, both on species richness and in terms of functional diversity. Results give elements for future studies on the effect of IAS on the bryophytes colonizing coastal sand dunes.

Exploring the Dunes: The Correlations between Vegetation Cover Pattern and Morphology for Sediment Retention Assessment Using Airborne Multisensor Acquisition

Coastal sand dunes are highly dynamic aeolian landforms where different spatial patterns can be observed due to the complex interactions and relationships between landforms and land cover. Sediment distribution related to vegetation types is explored here on a single ridge dune system by using an airborne hyperspectral and light detection and ranging (LiDAR) remote sensing dataset. A correlation model is applied to describe the continuum of dune cover typologies, determine the class metrics from landscape ecology and the morphology parameters, and extract the relationship intensity among them. As a main result, the mixture of different vegetation types such as herbaceous, shrubs, and trees classes shows to be a key element for the sediment distribution pattern and a proxy for dune sediment retention capacity, and the anthropic fingerprints can play an even major role influencing both ecological and morphological features. The novelty of the approach is mostly based on the synergistic use of LiDAR with hyperspectral that allowed (i) the benefit from already existing processing methods to simplify the way to obtain thematic maps and coastal metrics and (ii) an improved detection of natural and anthropic landscape.

Adaptive responses of Limoniastrum monopetalum (L.) Boiss. growing naturally at different habitats

Limoniastrum monopetalum is a perennial halophyte growing at different habitats along the Mediterranean Sea coast of Egypt. The morpho-anatomical and physiological responses was investigated for L. monopetalum leaves collected from; wet salt marshes, coastal sand dunes and rocky ridges habitats. The plant acquired the highest values of leaf area, lamina thickness, specific leaf area and water content despite of the high salinity in the salt marshes habitat. Additionally, plant is able to regulate content of Na+, Cl−, K+, Ca2+, Mg2+, accumulate proline and total phenols. On the other hand, plants growing in the driest habitats (coastal sand dunes and rocky ridges) acquired xeromorphic features viz., thick cuticle, compacted palisade tissue, increasing lignification of sclerified tissue and ash content. Moreover, plants in coastal sand dunes displayed extra adaptive responses viz., increase in chl. a, chl. b, carotenoids, K+ and Cl−, palisade ratio and stomatal densities. Plants growing at rocky ridges were affected by drought and salinity together. Those acquired the highest Na+ and Na+/K+, associated with the lowest in osmotic potential. In general, L. monopetalum able to exclude salt outside cells via salt glands scattered on leaf surfaces. These mechanisms permit L. monopetalum to tolerate and survive under stressful coastal habitats of Egypt.

Coastal landscape evolution in the Wilpattu National Park (NW Sri Lanka) linked to changes in sediment supply and rainfall across the Pleistocene–Holocene transition

Coastal sand dunes are sediment archives which can be used to reconstruct periods of aridity and humidity, past wind strength and variations in the sediment supply related to sea‐level changes. In this manner, the sedimentary record of fossil coastal dunes in Sri Lanka provides evidence for environmental and climatic changes during the late Pleistocene and Holocene. As yet, these environmental shifts are poorly resolved because the sedimentary facies and their depositional architecture have not been studied and only very few age constraints are available. Facies analysis of a lithological section at the Point Kurdimalai sea cliff in the Wilpattu National Park (NW Sri Lanka) reveals a striking resemblance to the stratigraphic succession associated with the Teri Sands in southeastern India, which is better dated. The reason is that deposition occurred under the same geological, climatic and geomorphological conditions in the two regions. This special situation allows for litho‐ and climate stratigraphic correlations across the Gulf of Mannar and links the landscape evolution at Point Kudrimalai to late Quaternary climatic events and sea‐level changes. Our results show that the formation of red coastal dunes (Red Beds) in Sri Lanka was a multi‐phase process across the Pleistocene–Holocene boundary and hence the differentiation between an Older Group of Plio‐Pleistocene age (including the Red Beds) and a Younger Group of Holocene age in the Quaternary stratigraphic chart for Sri Lanka is not justified.

Enough Is Enough? Searching for the Optimal Sample Size to Monitor European Habitats: A Case Study from Coastal Sand Dunes

A robust survey method that samples the main characteristics of plant assemblages is needed to assess the conservation status of European habitat in the Natura 2000 network. A measure of variability, called pseudo-multivariate dissimilarity-based standard error (MultSE), was recently proposed for assessing sample-size adequacy in ecological communities. Here, we used it on coastal sand dune systems in three Special Areas of Conservation (SACs) in Tuscany. Our aim was to assess the minimum number of replicates necessary to adequately characterize sand dune environments in terms of differences between habitats and SACs, after a preliminary baseline assessment of plant diversity. Analysis of α and β diversity indicated that especially between habitats the three SACs protect different plant communities. The study of the MultSE profiles showed that the minimum number of replicates needed to assess differences among habitats varied between 10 and 25 plots. Two-way PERMANOVA and SIMPER analysis on the full and reduced datasets confirmed that SACs and habitats host different plant communities, and that the contribution of the target species remained unchanged even with a reduced sample size. The proposed methodological approach can be used to develop cost-effective monitoring programs and it can be useful for plant ecologists and biodiversity managers for assessing ecosystem health and changes.

Seasonal shifts of arbuscular mycorrhizal fungi in Cocos nucifera roots in Yucatan, Mexico.

The diversity and community structure of arbuscular mycorrhizal fungi (AMF) associated with coconut (Cocos nucifera) roots was evaluated by next generation sequencing (NGS) using partial sequences of the 18S rDNA gene and by spore isolation and morphological identification from rhizosphere soil. Root samples from six different Green Dwarf coconut plantations and from one organic plantation surrounded by tropical dry forest along the coastal sand dunes in Yucatan, Mexico, were collected during the rainy and dry seasons. In total, 14 root samples were sequenced with the Illumina MiSeq platform. Additionally, soil samples from the dry season were collected to identify AMF glomerospores. Based on a 95-97% similarity, a total of 36 virtual taxa (VT) belonging to nine genera were identified including one new genus-like clade. Glomus was the most abundant genus, both in number of VT and sequences. The comparison of dry and rainy season samples revealed differences in the richness and composition of AMF communities colonizing coconut roots. Our study shows that the main AMF genera associated with coconut tree roots in all samples were Glomus, Sclerocystis, Rhizophagus, Redeckera, and Diversispora. Based on glomerospore morphology, 22 morphospecies were recorded among which 14 were identified to species. Sclerocystis sinuosa, Sclerocystis rubiformis, Glomus microaggregatum, and Acaulospora scrobiculata were dominant in field rhizosphere samples. This is the first assessment of the composition of AMF communities colonizing coconut roots in rainy and dry seasons. It is of importance for selection of AMF species to investigate for their potential application in sustainable agriculture of coconut.

Canonical Correspondence Analysis Ordinations and Competitor, Stress Tolerator, and Ruderal Strategies of Coastal Dune Plants in South Korea

Lee, J.-S.; Son, D.-H.; Lee, S.-H.; Myeong, H.-H.; Cho, J.-S.; Lee, J.-C.; Lee, J.-Y.; Park, C.-S., and Kim, J.-W., 2020. Canonical correspondence analysis ordinations and competitor, stress tolerator, and ruderal strategies of coastal dune plants in South Korea. Journal of Coastal Research, 36(3), 528–535. Coconut Creek (Florida), ISSN 0749-0208.The distribution of plant communities in the sand dunes of the SW coasts of South Korea was studied, along with environmental factors and plant traits, by canonical correspondence analysis (CCA). The competitor, stress tolerator, and ruderal (CSR) ecological strategies were also evaluated. The coastal sand dune plants were classified into two plant trait groups in the CCA biplot diagram. First, vegetation was correlated with leaf dry weight, canopy height, specific leaf area, leaf dry matter content, and lateral spread. Second, it was correlated with the flowering period and flowering start. Coastal sand dune plants were classified into three soil factor groups in axes 1 and 2 of the CCA biplot diagram. First, the vegetation was correlated with total nitrogen (T-N), K+, Silt, Mg2+, Na+, and clay contents. Second, it was correlated with Ca2+. Third, it was correlated with the sand contents. To elucidate the relative significance of competition, stress, and disturbance in the distribution process of plant communities, the CSR distribution model was adopted. Many coastal plants (12 species) showed competitor-ruderal/competitor-stress-tolerant-ruderal strategies: Artemisia fukudo, Atriplex gmelinii, Carex kobomugi, Calystegia soldanella, Digitaria ciliaris, Linaria japonica, Messerschmidia sibirica, Oenothera bieenis, Salicornia europaea, Salsola komarovii, Suaeda glauca, and Suaeda maritima. The four species with stress-tolerant-competitor/competitor-stress-tolerant-ruderal strategies were Carex pumila, Imperata cylindrica var. koenigii, Limonium tetragonum, and Zoysia sinica. Conyza canadensis, Ischaemum anthephoroides, Phragmites communis, and Vitex rotundifolia displayed competitor/stress-tolerant-competitor, competitor-ruderal, stress-tolerant-competitor, and C/SC strategies, respectively. The differences in distribution and restoration patterns of the CCA diagrams and CSR triangles may be attributable to different adaptions of plant traits or soil factors.

Measuring the effect of wind-driven processes on coastal dunes: a study of the Atlantis and Geelbek dune fields along the West Coast of South Africa

Dunes are dynamic features that can change location, shape or extent depending on wind direction and strength, the vegetation cover, temperature and moisture. This study focus on the primary factors impacting the change dynamics of sand dunes which are wind direction and wind strength. Two methods exist for measuring and detecting sand dune movements, namely, in situ surveys and change detection through remote sensing. This study applied change detection through remote sensing by using satellite imagery as methodology to monitor the movement and extent of change of two prominent coastal sand dunes located along the West Coast of South Africa. The significance of this study is to highlight the changes that occurred in the Atlantis and Geelbek coastal dune fields over the period 1998 to 2018 ascribable to the effect of wind-driven processes. The results showed that both these two dunes experienced more or less the same extent of movement and the direction of movement correlated well with the direction of the stronger summer wind-driven processes on the West Coast. However, it was also recorded that the extent of change of the dune fields were irregular.

Effects of sand dune, desert and field arbuscular mycorrhizae on lettuce (Lactuca sativa, L.) growth in a natural saline soil

Inoculation with arbuscular mycorrhizal fungi (AMF) improves plant growth under saline stress. We hypothesized that AMF originally isolated from coastal sand dunes would be adapted to saline stress and as a result they would be more efficient in promoting lettuce (Lactuca sativa, L.) growth under saline conditions compared to AMF from desert or agricultural soil. In addition, we investigated potential mechanisms that they may induce to the plant to cope with salinity stress. Pre-inoculated with AMF from coastal sand dunes (Innospora spp and Diversispora spp), non-saline field (Rhizophagus intraradices) or desert (Septoglomus deserticola) or non-inoculated lettuce plants were transplanted in pots with a saline soil (EC 12.79 dS m−1). The plants were harvested at 15, 30 and 45 days after transplantation and the root and shoot biomass, AMF root colonization, chlorophyll (SPAD value), proline concentration, root and leaf phosphorus, potassium, and sodium concentrations were measured. The coastal sand dune isolates were not more efficient in promoting lettuce growth than the isolates originating from desert or field soil, with lettuce plants having equal leaf biomass with all inocula, however they differed by inducing better lettuce root growth, higher total K uptake and lower proline shoot concentration. In addition, we found that proline concentration varied with time and it peaked at 30 days and then decreased at 45 days. The results provide an indication that although different AMF induced different plant strategies to cope with salinity, their ability to promote lettuce growth under high saline conditions may not be related with their origin.

Significance of soil properties and microbial activity on soil co emission in coastal sand dunes of Odisha, India

Significance of soil properties and microbial activity on soil co emission in coastal sand dunes of Odisha, India

해안사구 식생의 침입종에 의한 종조성 변화에 관한 연구 - 진도ㆍ완도ㆍ해남을 중심으로-

해안사구 식생의 침입종에 의한 종조성 변화에 관한 연구 - 진도ㆍ완도ㆍ해남을 중심으로-

Migration of Pleistocene shorelines across the Palaeo-Agulhas Plain: Evidence from dated sub-bottom profiles and archaeological shellfish assemblages

Intertidal zones on shorelines are geologically complex features of the coastal plain, shaped by heterogeneous substrate lithologies. Palaeocoastlines have been heavily modified by sea-level change, ocean currents, wind, waves and swell. Rocks and sediments along intertidal zones create rich habitats for biogenic forms including shellfish, which are highly sensitive to subtle variations in underlying lithology. Here, we assess Pleistocene shoreline migrations on the south coast of South Africa in relation to fluctuating sea-levels and changes in sediment supply. The study area extends from Still Bay to Mossel Bay, South Africa, with a particular focus on Pinnacle Point. Our goal is to better understand the changes to the intertidal zone along these palaeocoastlines and how this may have affected marine resources available to early humans. We interpret marine geological records at select time slices along sub-bottom profiled transects that run perpendicular to the coast. We describe the character of specific shorelines to establish expectations of coastline character which we then compare to archaeological records at Pinnacle Point. We base our interpretations on (1) significant events in Pleistocene glacio-eustatic and depositional records, such as widespread deposition of coastal sand dunes at ∼90, ∼74 and ∼50 ka [MIS 5e–MIS 4], and (2) empirical evidence from high-resolution records of shellfish assemblages at the archaeological sites of PP13B and PP5-6. We demonstrate a prevalence of dissipative beaches and mixed coasts on Pleistocene sea-level lowstands on the coast of the Palaeo-Agulhas Plain. This differs significantly from the modern coastline with its significance of rocky shorelines.

Observing Geomorphological Change on an Evolving Coastal Sand Dune Using SLAM-Based UAV LiDAR

Following over 20 years of manned airborne LiDAR in the remote sensing of geomorphological change in coastal environments, rapid advancements in unmanned aerial vehicle (UAV) technologies have expanded the possibilities of acquiring very high-resolution data efficiently over spatial-temporal scales not previously feasible. This study employed a new Simultaneous Localisation and Mapping (SLAM)–based LiDAR system (“Hovermap”) across a segment of coastal sand dune of Bribie Island, Queensland, Australia. The study area was identified by the local council as an area of interest over concern that continued erosion at an existing blowout could result in cutting off northern Bribie Island and adversely affect hydrodynamic processes of Pumicestone Passage, its shoreline, and its associated infrastructure. Here, we employed the Hovermap within a multi-temporal design in which four, quarterly, surveys undertaken over a 9-month period from July 2017 to April 2018. On the first survey, a Leica P40 (P40) terrestrial laser scanner (TLS) was also deployed across the study area to facilitate a performance comparison. Hovermap reported a mean point cloud density of 2532 ± 170 pts.·m-2, ground sample distance (GSD) of 0.02 ± 0.001 m, and RMSE of 0.050 ± 0.31 m relative to ground control points (GCPs). Three-dimensional mesh objects were derived from all point clouds obtained and evaluated in terms of elevation and slope with mesh-to-mesh deviations and volumetric change (cubature) analysis examined over consecutive surveys. The Hovermap closely matched results of the P40 with measures of elevation and slope differing by approximately 2% and 7%, respectively. Mean vertical deviation (0.01 ± 0.03 m) and cubature (~ 2.5 m3 net difference) results also showed close agreement. Due to stable wave conditions between the first three surveys, minimal changes in beach topography were observed, whilst pronounced erosion and scarping of the foredune were measured during the final survey. This erosion was evidenced from changes in mean elevation (− 16%), slope (+ 25%), and deviation (+ 86%) relative to the mean measurements over the first three survey dates. In addition, a net loss of approximately -1295 m3 of sand was measured between the final two survey dates (January–April 2018). This is supported by local marine weather data in which a significant increase in local wind speeds (ANOVA, F(1,180) = 6.257, p = 0.013) and wave heights (ANOVA F(1,180) = 41.769, p ≤ 0.001) were recorded over the same interval. The results presented here are first to demonstrate that UAV LiDAR performance was robust in a typical, moderate-energy, sandy beach and is suited for the detection and evaluation of coastal morphologic change at microspatial and temporal scales.

Association of Community-level Traits with Soil Properties in a Tropical Coastal Sand Dune

There is limited information regarding plant functional traits for plant communities in tropical coastal sand dunes. This study investigated differences in species trait compositions and the relationship between community-weighted mean (CWM) traits and soil properties on the windward and leeward sides of the Bang Boet coastal sand dunes in southern Thailand. Ten sampling plots were randomly selected from each side of the dune. All woody plant species were collected and their functional traits were assessed. Soil samples were also collected. A redundancy analysis (RDA) was used to examine the relationship between CWM traits and soil properties. The results showed that species trait compositions and the CWMs of specific leaf area, leaf thickness, and leaf toughness were significantly different between windward and leeward sides. The RDA showed significant correlation between CWM traits and soil properties, particularly for specific leaf area, a functional trait that plays an important role in nutrient turnover on the leeward side. These results indicate that soil properties are predictable based on CWM traits and that leeward sand dune sides can support greater soil formation than windward sides. Hence, functional traits, as well as species, should be considered in coastal sand dune restoration and conservation programs.

Analysis of Forest Cover Loss in <em>Wilpattu</em> forest complex: a remotely sensed change detection and fragmentation analysis

Wilpattu Forest complex is the largest protected area in Sri Lanka and it is a designated Ramsar wetland cluster. It contains a range of diverse terrestrial habitats including various forest types and a coastline with large coastal sand dunes. However, this vital ecosystem is under threat of fragmentation and degradation due to increasing human interventions. Habitat fragmentation is a serious threat to the rich biodiversity in this ecosystem. The objective of this study was to assess the loss of forest cover within the region, to examine the spatial pattern of forest cover fragmentation and to predict the potential forest cover change in 2025 using remote sensing and GIS techniques. Two Landsat 5 TM satellite images of 1992 and Landsat 8 OLI-TIRS image of 2018 were classified using unsupervised and supervised techniques to obtain three land use/ land cover classes namely, forest, nonforest and water. Forest cover change during 1992 and 2018 was analysed using classified images. Finally, future changes were modelled to assess possible threat to the forest cover. The analysis revealed that Wilpattu forest complex has lost 19,524 ha of its forest reserves to other land uses within the last 26 years and the highest impact was seen in the upper Wilpattu forest where about 7.48% area has lost from forest to other land uses. Study also proved that the total forest area is becoming more fragmented affecting the balance of the valuable natural eco-system of the area. Lack of availability in proper forest boundaries and classification issues were identified as main limitations in this study. However, it must be emphasized that immediate actions are needed to prevent further degradation of this sensitive ecosystem.